592 MURIDyE— EPIMYS 



vestigial and may be wholly absent ; m^ appears to be rather more 

 simplified than in norvegicus, but the posterior lobe when quite unworn 

 shows distinct traces of cusps 4 and y. 



Exceptional variation : — Individuals with a white chest spot, some- 

 times of very large size, or a median stripe of white, are not infrequent 

 in E. r. rattus, and have been observed at Yarmouth by Patterson ; 

 similarly, individuals with a dusky patch or stripe are often found 

 among the light-bellied forms. From the experimental breeding of 

 norvegicus performed by Crampe, Doncaster, and Mudge, it would 

 appear that such patterns are the subjects of Mendelian inheritance 

 independently of the colour. A white-spotted r. rattus, from 

 Kongsberg, Norway, has been recorded by Collett. Rarely, an 

 ochraceous patch is seen on the ventral surface just behind either the 

 right or the left fore limb (B.M., Nos. i.i 1.3.26, Brazil, alexandrinus ; 

 8.9.12.2, British New Guinea, rattus ; both males). In some forms, 

 particularly in the young, a white spot is present on the forehead: 

 on such a variation from the Punjab, Mus brahminicus of Lloyd {Rec. 

 Indian Mus., iii., 1909, 22) is based ; Fatio (p. 199) describes, from the 

 neighbourhood of Geneva, a colony of Black Rats in which, young and 

 old alike, all were characterised for many consecutive years by the 

 presence of a conspicuous white lock on the centre of the forehead. 

 Albino specimens have been known from the time of Gesner (see 

 Kolazy, Verh. Zool.-bot. Ges., Wien., 1871, 731, and belpw under nor- 

 vegicus). According to Patterson {Zoologist, 1907, 69), a male from 

 Yarmouth was of a very pale blue-white colour and. had fiery red eyes ; 

 its creamy white tail was rather shorter than usual. As is the case with 

 norvegicus, a hairless variety, due to disease, is known (T. E. Belcher, 

 Zoologist, 1904, 72 ; and J. Woodward, Field, 19th August 1905, 378). 



Bellermann^ said that "'very often six to eight lie together and 

 entwine their tails as closely as if they were fused with each other. 

 Such a nest is called a 'King Rat.'" Blasius (319), repeating this 

 curious statement, apparently on his own authority, says that the tails 

 are fused, and that as such individuals are incapable of moving freely 

 in the search for food, they must be fed by their parents or by other 

 rats ; hence the name Rattenkonig. 



Greographical variation : — This species is represented in the Oriental 

 region by a great number of named forms, but the status of many of 

 these is still far from being satisfactorily determined. Oldfield Thomas 

 {Proc. Zool. Soc, London, 1881, 533) arranged the Indian members of 



' Daseyn des RattenMniges, 1820. Oken, Allgem. Naturgesch., 7, Abt. i, 719. A 

 belief in " King Rats," dating at least from Gesner {De Quadr., i., 829), is widely 

 spread in Germany and in the German idiom, " ein Rattenkonig von Unwahrschein- 

 /zVM«V«»" = "a perfect maze of improbabilities" (see Muret-Sanders, Emyclop. 

 Worterbuch ; J. and W. Grimm, Deutsches Worterbuch, 1893). Schreber, long ago, 

 dismissed this belief as " a mere and very badly contrived fable." 



